:root {
  --paper: #f5f5f1;
  --card: #ffffff;
  --ink: #161d33;
  --muted: #5d6579;
  --line: #e2e3e0;
  --navy: #1a2352;
  --navy-line: #39427a;
  --on-navy-muted: #b9c0dc;
  --accent: #2148d4;
  --orange: #d9441a;
  --danger: #c0352b;
  --kakao: #fee500;
  --kakao-ink: #191600;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 80px; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}
body {
  margin: 0;
  background: var(--card);
  color: var(--ink);
  font-family: "Pretendard Variable", Pretendard, "Apple SD Gothic Neo", "Malgun Gothic", sans-serif;
  font-size: 16px;
  line-height: 1.6;
  word-break: keep-all;
  overflow-wrap: break-word;
}
img { display: block; max-width: 100%; height: auto; }
a { color: inherit; }
h1, h2, h3, p, ul { margin: 0; }
ul { padding: 0; list-style: none; }

.wrap { width: min(1120px, 100%); margin: 0 auto; padding: 0 24px; }

/* 상단 메뉴 */
.nav {
  position: sticky;
  top: 0;
  z-index: 10;
  background: var(--card);
  border-bottom: 1px solid var(--line);
}
.nav .wrap {
  display: flex;
  align-items: center;
  gap: 28px;
  height: 64px;
}
.logo {
  margin-right: auto;
  font-size: 18px;
  font-weight: 800;
  letter-spacing: -0.01em;
  text-decoration: none;
}
.nav-link {
  display: flex;
  align-items: center;
  min-height: 44px;
  color: var(--muted);
  font-size: 15px;
  font-weight: 600;
  text-decoration: none;
}
.nav-link:hover { color: var(--ink); }

/* 버튼 */
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 54px;
  padding: 0 28px;
  border: 0;
  border-radius: 12px;
  background: var(--kakao);
  color: var(--kakao-ink);
  font: inherit;
  font-size: 16px;
  font-weight: 700;
  cursor: pointer;
}
.button:hover { filter: brightness(0.96); }
.button svg { width: 20px; height: 20px; flex: none; }
.button.small { min-height: 44px; padding: 0 16px; font-size: 14px; border-radius: 10px; }
a:focus-visible, button:focus-visible, textarea:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* 첫 화면: 프로필과 사진이 스크롤 없이 한 번에 보이도록 구성 */
.hero .wrap {
  display: grid;
  grid-template-columns: 6fr 5fr;
  gap: 32px;
  height: clamp(540px, calc(100svh - 104px), 720px);
}
.hero-info {
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-height: 0;
}
.role { color: var(--accent); font-size: 15px; font-weight: 700; }
.hero h1 {
  margin-top: 4px;
  font-size: 48px;
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.02em;
}
.tagline {
  margin-top: 14px;
  font-size: 24px;
  font-weight: 700;
  line-height: 1.4;
  letter-spacing: -0.01em;
}
.tagline em { color: var(--accent); font-style: normal; }
.profile {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  margin-top: 24px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
}
.profile h2 {
  margin-bottom: 6px;
  color: var(--muted);
  font-size: 13px;
  font-weight: 600;
}
.profile ul { font-size: 15px; line-height: 1.65; }
.hero-info .button { align-self: flex-start; margin-top: 28px; min-width: 260px; }
.hero-photo { position: relative; min-height: 0; }
.hero-photo img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center top;
}

/* 공통 섹션 */
.section { padding: 88px 0; }
.section.paper { background: var(--paper); }
.section.navy { background: var(--navy); color: #fff; }
.label {
  color: var(--accent);
  font-size: 14px;
  font-weight: 700;
}
.navy .label { color: var(--kakao); }
.section h2.title {
  margin-top: 6px;
  font-size: 34px;
  font-weight: 800;
  line-height: 1.3;
  letter-spacing: -0.02em;
}
.section-lead { margin-top: 12px; color: var(--muted); font-size: 17px; }

/* 학생 전용 링크 */
.student-links { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; margin-top: 36px; }
.student-link {
  display: grid; grid-template-columns: auto 1fr auto; gap: 18px; align-items: center;
  padding: 26px 24px; border: 1px solid var(--line); border-radius: 16px;
  background: var(--card); text-decoration: none;
  transition: border-color .15s, box-shadow .15s, transform .15s;
}
.student-link:hover { border-color: var(--navy); box-shadow: 0 14px 30px -20px rgba(26, 35, 82, .5); transform: translateY(-2px); }
.sl-icon { display: grid; place-items: center; width: 52px; height: 52px; border-radius: 14px; background: var(--navy); color: #fff; }
.student-link.ask .sl-icon { background: var(--orange); }
.sl-icon svg { width: 26px; height: 26px; }
.sl-body { display: block; }
.sl-tag { display: block; color: var(--accent); font-size: 13px; font-weight: 700; }
.student-link.ask .sl-tag { color: var(--orange); }
.sl-title { display: block; margin-top: 2px; font-size: 21px; font-weight: 800; letter-spacing: -0.01em; }
.sl-desc { display: block; margin-top: 4px; color: var(--muted); font-size: 15px; line-height: 1.55; }
.sl-go { font-size: 22px; font-weight: 700; color: var(--muted); }
.student-link:hover .sl-go { color: var(--navy); }
@media (prefers-reduced-motion: reduce) { .student-link { transition: none; } .student-link:hover { transform: none; } }

/* 수업 소개 */
.classes {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin-top: 40px;
}
.class {
  padding: 32px;
  border-radius: 16px;
  background: var(--card);
}
.class .who { color: var(--muted); font-size: 14px; font-weight: 600; }
.class h3 { margin-top: 4px; font-size: 24px; font-weight: 800; letter-spacing: -0.01em; }
.class > p { margin-top: 10px; color: var(--muted); }
.class ul { margin-top: 18px; padding-top: 16px; border-top: 1px solid var(--line); }
.class li {
  position: relative;
  padding: 4px 0 4px 18px;
  font-weight: 500;
}
.class li::before {
  content: "";
  position: absolute;
  top: 15px;
  left: 2px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
}

/* 수업 원칙 */
.principles {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 40px;
  margin-top: 44px;
}
.principle { padding-top: 18px; border-top: 1px solid var(--navy-line); }
.principle .num { color: var(--kakao); font-size: 15px; font-weight: 700; }
.principle h3 { margin-top: 8px; font-size: 21px; font-weight: 700; line-height: 1.4; }
.principle p { margin-top: 10px; color: var(--on-navy-muted); font-size: 15px; }

/* 교재 */
.stages { display: grid; gap: 44px; margin-top: 44px; }
.stage {
  display: grid;
  grid-template-columns: 4fr 7fr;
  gap: 40px;
  align-items: center;
}
.stage h3 { font-size: 32px; font-weight: 800; letter-spacing: -0.01em; }
.stage.prep h3 { color: var(--accent); }
.stage.crack h3 { color: var(--orange); }
.stage .level { margin-top: 4px; font-weight: 600; }
.stage p:last-child { margin-top: 10px; color: var(--muted); }
.covers { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; }
.covers img { width: 100%; border-radius: 6px; box-shadow: 0 8px 24px rgb(16 24 40 / 14%); }
.spread-title { font-size: 18px; font-weight: 700; }
.stage p.hint { margin-top: 8px; font-size: 14px; }
.spread { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.spread a { display: block; border-radius: 6px; }
.spread img { width: 100%; border: 1px solid var(--line); border-radius: 6px; box-shadow: 0 8px 24px rgb(16 24 40 / 10%); }
.spread a:hover img { border-color: var(--accent); }

/* 칼럼 목록 */
.column-list {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  margin-top: 40px;
}
.column-card { display: block; text-decoration: none; }
.column-card img { width: 100%; aspect-ratio: 1; object-fit: cover; border-radius: 12px; }
.column-card .meta { margin-top: 14px; color: var(--muted); font-size: 13px; font-weight: 600; }
.column-card h3 { margin-top: 4px; font-size: 17px; font-weight: 700; line-height: 1.45; }
.column-card:hover h3 { color: var(--accent); }

/* 문의 */
.contact { text-align: center; }
.contact h2 { font-size: 32px; font-weight: 800; line-height: 1.35; letter-spacing: -0.02em; }
.contact p { margin-top: 10px; color: var(--on-navy-muted); }
.contact .button { margin-top: 28px; min-width: 260px; }

.footer { padding: 28px 0; color: var(--muted); font-size: 14px; }

/* 칼럼 본문 */
.article { width: min(760px, 100%); margin: 0 auto; padding: 56px 24px 72px; }
.article .meta { color: var(--accent); font-size: 14px; font-weight: 700; }
.article h1 {
  margin-top: 8px;
  font-size: 34px;
  font-weight: 800;
  line-height: 1.35;
  letter-spacing: -0.02em;
}
.article h2 {
  margin-top: 56px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
  font-size: 24px;
  font-weight: 800;
  line-height: 1.4;
}
.article h3 { margin-top: 44px; font-size: 19px; font-weight: 700; line-height: 1.45; }
.article p, .article ul { margin-top: 16px; font-size: 17px; line-height: 1.8; }
.article .lead { margin-top: 24px; }
.article li { padding-left: 16px; text-indent: -16px; }
.article li::before { content: "· "; font-weight: 700; }
.article figure { margin: 28px 0 0; }
.article figure img { width: 100%; border: 1px solid var(--line); border-radius: 12px; }
.note {
  padding: 16px 20px;
  border-radius: 10px;
  background: var(--paper);
  font-size: 16px !important;
}
.note strong { color: var(--accent); }
.article-cta {
  margin-top: 56px;
  padding: 32px;
  border-radius: 16px;
  background: var(--navy);
  color: #fff;
  text-align: center;
}
.article-cta p { margin: 0 0 18px; font-size: 18px; font-weight: 700; line-height: 1.5; }
.back { display: inline-flex; align-items: center; min-height: 44px; margin-top: 24px; color: var(--muted); font-weight: 600; }

/* 문의 창 */
dialog {
  width: min(480px, calc(100vw - 32px));
  padding: 28px;
  border: 0;
  border-radius: 18px;
  background: var(--card);
  color: var(--ink);
}
dialog::backdrop { background: rgb(10 14 20 / 55%); }
.dialog-head { display: flex; align-items: center; justify-content: space-between; }
.dialog-head h2 { font-size: 20px; font-weight: 700; }
.close {
  width: 44px;
  height: 44px;
  margin: -8px -10px -8px 0;
  border: 0;
  border-radius: 10px;
  background: none;
  color: var(--muted);
  font: inherit;
  font-size: 24px;
  cursor: pointer;
}
.guide { margin: 8px 0 14px; color: var(--muted); font-size: 14px; line-height: 1.55; }
textarea {
  display: block;
  width: 100%;
  height: 170px;
  margin-bottom: 14px;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--card);
  color: var(--ink);
  font: inherit;
  font-size: 16px;
  line-height: 1.5;
  resize: vertical;
}
textarea::placeholder { color: var(--muted); }
dialog .button { width: 100%; }
.status { margin: 12px 0 0; font-size: 14px; font-weight: 600; line-height: 1.5; }
.status:empty { display: none; }
.status.error { color: var(--danger); }
.status.ok { color: var(--accent); }

/* 태블릿 */
@media (max-width: 1000px) {
  .column-list { grid-template-columns: repeat(2, 1fr); }
  .student-links { grid-template-columns: 1fr; }
  .stage { grid-template-columns: 1fr; gap: 20px; }
  .principles { gap: 24px; }
  .hero h1 { font-size: 40px; }
  .tagline { font-size: 21px; }
  .profile { grid-template-columns: 1fr; gap: 14px; margin-top: 18px; padding-top: 14px; }
  .hero-info .button { margin-top: 20px; }
}

/* 휴대폰: 사진을 위로 올려 프로필이 한 화면에 들어오도록 맞춤 */
@media (max-width: 720px) {
  .wrap { padding: 0 20px; }
  .nav .wrap { height: 56px; gap: 14px; }
  .nav-link.optional { display: none; }
  .logo { font-size: 17px; }
  html { scroll-padding-top: 68px; }
  .student-links { grid-template-columns: 1fr; gap: 12px; margin-top: 28px; }
  .student-link { gap: 14px; padding: 20px 18px; }
  .sl-icon { width: 46px; height: 46px; }
  .sl-title { font-size: 19px; }
  .sl-desc { font-size: 14px; }

  .hero .wrap {
    grid-template-columns: 1fr;
    grid-template-rows: minmax(120px, 1fr) auto;
    gap: 0;
    height: auto;
    min-height: calc(100svh - 57px);
    padding: 0;
  }
  .hero-photo { order: -1; }
  .hero-info { padding: 14px 20px 18px; }
  .role { font-size: 13px; }
  .hero h1 { margin-top: 0; font-size: 28px; }
  .tagline { margin-top: 4px; font-size: 16px; }
  .profile { gap: 8px; margin-top: 10px; padding-top: 10px; }
  .profile h2 { margin-bottom: 2px; font-size: 12px; }
  .profile ul { font-size: 14px; line-height: 1.45; }
  .hero-info .button { align-self: stretch; margin-top: 14px; }

  .section { padding: 60px 0; }
  .section h2.title { font-size: 27px; }
  .section-lead { font-size: 16px; }
  .classes, .principles { grid-template-columns: 1fr; }
  .classes { margin-top: 28px; gap: 14px; }
  .class { padding: 24px 20px; }
  .principles { margin-top: 28px; }
  .stages { margin-top: 28px; gap: 36px; }

  .column-list { grid-template-columns: 1fr; gap: 18px; margin-top: 28px; }
  .column-card { display: grid; grid-template-columns: 104px 1fr; gap: 0 14px; align-items: start; }
  .column-card img { grid-row: 1 / 3; }
  .column-card .meta { margin-top: 0; }
  .column-card h3 { font-size: 16px; }

  .contact h2 { font-size: 25px; }
  .contact .button { width: 100%; }

  .article { padding: 36px 20px 56px; }
  .article h1 { font-size: 26px; }
  .article h2 { margin-top: 44px; font-size: 21px; }
  .article p, .article ul { font-size: 16px; }
  dialog { padding: 22px 20px; }
}